A dangerous heat pattern is expected to expand across much of the United States this week, bringing triple-digit temperatures, oppressive humidity, little overnight relief, and growing concerns about heat-related illness, according to meteorologist Ryan Hall of Ryan Hall, Y’all.
Hall said a large area of high pressure, often described as a heat dome, is building across the southern tier and will likely spread farther north and west as the week continues. The result could be several days of dangerous conditions from the Gulf Coast and southern Plains into parts of the High Plains and Midwest.
“A massive heat dome is going to continue to bake all of us,” Hall said, warning that the pattern may not be a brief summer warm spell.
Instead, he said, the heat could lock in through the middle of July, with some areas facing temperatures near or above 110 degrees and heat index values far higher.
At the same time, Hall said a separate storm system could bring severe weather and flash flooding to the Upper Midwest, while wildfire danger increases across parts of the Pacific Northwest and interior West.
Heat Dome Expands Across The South
Hall described the developing heat dome as a broad area of high pressure that traps sinking hot air near the surface.
He compared it to “a lid slamming down on a boiling pot,” with heat building underneath and little room for cooler air or storms to break through.
The first major focus is expected to be the South, especially areas south of Highway 84 in Mississippi, where Hall said heat index values could climb well into the triple digits.
Florida is another major concern.
Hall said extreme heat risk is expected to increase by Wednesday and remain in place through the weekend. The state may see several consecutive days of high humidity and heat indices that make outdoor work, exercise, and even short errands more dangerous.
The problem is not only afternoon heat. Hall emphasized that overnight temperatures may remain unusually warm in larger cities, with some lows struggling to fall below 85 degrees.
That lack of nighttime relief is one of the most serious parts of a prolonged heat event. When temperatures stay high after sunset, the body has less opportunity to cool down and recover before the next day begins.
For people without reliable air conditioning, older adults, young children, outdoor workers, and those with chronic health conditions, a run of hot nights can be as dangerous as the daytime highs.
Southern Plains Could See Triple-Digit Temperatures
By midweek, Hall said the hottest weather is expected to push farther west into North Texas and western Oklahoma.
Thursday could be the hottest day of the week across the southern Plains, with North Texas potentially reaching 100 degrees or higher. Hall said Dallas-Fort Worth may hold near 98 degrees at times because of clouds, but he stressed that temperatures near that level are still dangerous.
New Orleans could also see heat-advisory conditions on a daily basis, according to Hall’s forecast.
There may be isolated storms across North Texas and Louisiana early in the week, but Hall said those chances could fade as the high-pressure ridge strengthens later in the week.
That is an important shift because afternoon storms can sometimes provide brief cooling, even when they are disruptive. Once the ridge becomes stronger, clouds and thunderstorms may become less common, leaving communities exposed to direct sun and hotter temperatures for longer periods.
Hall said the heat dome is expected to keep spreading.
By the weekend, he expects the hottest air to expand into the central Rockies and farther north into the High Plains. South Dakota and Nebraska could see temperatures in the 110- to 115-degree range by Sunday if the forecast pattern develops as expected.
Even Minneapolis could have a chance of reaching 100 degrees early next week.
That is where the forecast becomes especially striking. Extreme heat in Texas, Oklahoma, and parts of the Deep South is familiar during summer, but when the heat pushes north into the Plains and Upper Midwest, many communities may be less prepared for several days of unusually high temperatures.
Heat Could Last Into Mid-July
Hall said the larger concern is how long the pattern could remain in place.
A short-lived heat wave can be difficult, but people often know relief is coming. A locked-in pattern that lasts for more than a week can put much greater pressure on electric grids, water systems, health services, and households that are already struggling with high cooling costs.
Hall said a brief weakness in the upper-level pattern was helping keep places such as Memphis somewhat less extreme through Wednesday.
But he expects that break to disappear as high pressure expands eastward.
Once that happens, he said the “door slams shut,” with the southern Plains and lower Mississippi Valley moving deeper into the hotter pattern.
The week-two outlook, Hall said, continues to show a moderate risk of extreme heat from July 13 through July 17 across the southern Plains, lower Mississippi Valley, and desert Southwest.
That suggests the heat could remain a concern even after the current week ends.
Hall said moisture from the Gulf of Mexico could also push dew points higher across the Plains and parts of the eastern United States. That would increase heat index values, which are often more important to human health than the air temperature alone.
A temperature of 98 degrees can feel much worse when humidity is high enough to slow the body’s ability to cool itself through sweat.
Severe Storms Could Hit The Upper Midwest
While the South deals with building heat, Hall said the most serious severe-weather threat Tuesday will be farther north.
He highlighted a Level 2 out of 5 slight risk across central and eastern South Dakota into southern Minnesota, including the Minneapolis metro area.
A stalled cold front could trigger thunderstorms, and Hall said weak winds higher in the atmosphere may allow some storms to move slowly.
Slow-moving storms can create two different problems at once. They may produce large hail, damaging wind gusts, and isolated tornadoes, while also dumping heavy rainfall over the same areas for long periods.
Hall said he was highly confident that some storms would develop into supercells capable of producing quarter-size hail or larger. He also said there could be a narrow tornado window around sunset.
Later in the evening, storms could move toward eastern South Dakota and western Minnesota, producing wind gusts of 60 mph or higher after dark.
That nighttime timing matters because people may be asleep or less likely to notice a changing sky. Hall encouraged people from Sioux Falls to Minneapolis to make sure they have a reliable way to receive warnings overnight.
He also flagged a slight risk of excessive rainfall from the eastern Dakotas into central Wisconsin. A corridor near St. Cloud could see 1 to 3 inches of rain, with localized heavier totals possible.
Wednesday Brings More Flooding Concerns
By Wednesday, Hall said the same weather system should move east toward the Upper Mississippi Valley and Great Lakes.
The severe-weather risk may drop to a Level 1 marginal risk, with locally damaging winds becoming the main concern. Hall said hail may be less of a factor because the atmosphere could be too warm aloft.
But the bigger issue may be flash flooding.
Hall said eastern Minnesota, northern Wisconsin, and upper Michigan could see repeated heavy rain as the front moves slowly across the region.
He said parts of northern Wisconsin could have a 50% to 70% chance of receiving more than 2 inches of rain in a short period. Taylor County was among the areas he described as having a worse-case scenario if storms repeatedly track over the same locations.
Ground conditions are already saturated in some places, Hall said, which means creeks, drainage systems, and low-lying roads may flood quickly.
Flooding is often underestimated because the rain can seem less dramatic than a tornado or a hailstorm. But repeated thunderstorms over one community can create dangerous conditions in a matter of minutes, particularly at night or near creeks, intersections, and underpasses.
Fire Danger Builds Across The West
Hall also warned of rising wildfire danger across parts of the western United States.
The greatest concern Tuesday was expected across the lower Columbia Basin, the Warm Springs area, northeast California, Nevada, and parts of Oregon.
He said triple-digit heat, low humidity, and wind gusts near 30 mph could combine to create dangerous fire conditions.
Dry thunderstorms could make the situation worse.
Hall said Oregon could have a 70% chance of cloud-to-ground lightning without meaningful rainfall in some areas. That type of lightning can ignite dry vegetation without providing the rain needed to reduce fire danger.
“One spark” could create a major problem, Hall warned.
He urged people in fire-prone areas to avoid using outdoor machinery that could create sparks, avoid throwing cigarettes from vehicles, and keep evacuation bags ready in case a wildfire develops nearby.
That advice may sound basic, but wildfire conditions can turn ordinary mistakes into emergencies quickly when heat, wind, and dry vegetation all come together.
A Few Places May Escape The Extremes
Not every part of the country will face dangerous weather this week.
Hall pointed to the western Great Lakes and southwestern Michigan as an area that could see unusually pleasant conditions Tuesday, with highs in the mid-80s, low humidity, and clear skies.
Grand Rapids was one of the cities he mentioned as having dry air and dew points in the 50s, a sharp contrast to the sticky and dangerous heat building farther south.
He also said parts of the interior Pacific Northwest, including Medford, Oregon, could see clear skies and relatively comfortable humidity, though temperatures there may still be warm.
Those pockets of calm weather are worth noting because they show how uneven the larger pattern will be. While some areas face triple-digit heat, flooding, severe storms, or fire danger, other parts of the country may experience some of the best weather of the summer.
Still, Hall’s main message was clear: the heat dome is the biggest story.
The coming days could bring dangerous heat to millions of people, especially across the South and Plains, while storms and flooding create a separate set of hazards farther north.
Hall urged viewers to prepare early, stay hydrated, limit time outdoors during the hottest part of the day, and take warnings seriously.
This is not simply a hot stretch of July weather. If the pattern holds, it could become a prolonged heat event that changes how people work, travel, sleep, and stay safe for much of the middle of the month.
Growing up in the Pacific Northwest, John developed a love for the great outdoors early on. With years of experience as a wilderness guide, he’s navigated rugged terrains and unpredictable weather patterns. John is also an avid hunter and fisherman who believes in sustainable living. His focus on practical survival skills, from building shelters to purifying water, reflects his passion for preparedness. When he’s not out in the wild, you can find him sharing his knowledge through writing, hoping to inspire others to embrace self-reliance.
